In a web-offset printing press, a blanket cylinder receives an image from a printing plate cylinder and transfers the image to a web of paper. Multi-color web offset printing presses are known which apply a multi-color image to a face of a web via a single blanket cylinder, with two blanket cylinders being employed to print both sides of the web.
In a conventional multi-color single blanket system, a plurality of plate cylinders contact each blanket, each of the plate cylinders applying a different color image to the blanket. The blankets form a nip through which a web is passed. The web receives the multi-color image from each blanket. Such a device is described in U.S. Pat. No. 4,633,777 to Germann.
In some situations, it is desirable to print the multi-color image on a single side of a web, while in other situations it is desirable to print the multi-color image on both sides. In still other situations, it may be desirable to print a multi-color image on a single side of each of two webs. Known multi-color single blanket presses are not capable of selectively printing either on both sides of a single web or single sides of two webs.